(1) Field of the Invention
The present invention pertains to an actuator mechanism that adjusts the lateral spacing between pairs of flanges that define a conveying slot of an air conveyor. In particular, the present invention provides a mechanism that can be selectively controlled to adjust the lateral spacing of the slot between opposed flanges of an air conveyor employed in conveying plastic bottles suspended by their neck rings in the slot to quickly change over the air conveyor for conveying plastic bottles of different neck and neck ring diameters.
(2) Description of the Related Art
Air conveyors are typically employed in the rapid transport of empty plastic bottles of the type having an annular rim or a neck ring at the base of the bottle neck. A typical air conveyor includes a pair of flanges that are spaced from each other defining an elongated slot between the flanges. For air conveyors of considerable longitudinal length, conveyor sections are connected end-to-end so that the pairs of flanges of one section are aligned with the pairs of flanges of other adjacent conveyor sections and the slots of the pairs of flanges aligned end-to-end define the conveyor path. The spacings between the flanges of the conveyor sections is sufficiently large to enable a portion of the bottle neck just below the neck ring to pass through the spacing with the bottle suspended from the top surfaces of the flanges by the neck ring engaging on the top surfaces. A series of air ducts are positioned along the flanges above and/or below the flanges. A plenum of the air conveyor sections supplies a flow of air to the air ducts. The air ducts are oriented so that air ejected from the ducts will contact the plastic bottles pushing the bottles along the pathway defined by the elongated slots of the aligned pairs of conveyor flanges with the neck rings of the bottles sliding along the top surfaces of the pairs of flanges. An example of this type of conveyor is disclosed in the Ouellette U.S. Pat. No. 5,628,588, issued May 13, 1997 and incorporated herein by reference.
In some types of air conveyors the opposed flanges that define the slot of the conveyor path are mounted in laterally spaced side walls of the air conveyor that define a conveying channel between the side walls. The air ducts also pass through these pairs of side walls feeding the flow of air to the jets that also emerge from these side walls. The side walls are provided with mutually opposed, longitudinally extending grooves. The pairs of flanges are mounted in these grooves. The grooves are designed to be sufficiently deep so that the flanges can be adjustably positioned in the grooves enabling the pair of opposed flanges to be moved laterally toward each other or laterally away from each other. This enables the lateral spacing between the pairs of flanges that defines the conveyor slot to be adjusted to accommodate different diameter neck rings of bottles to be conveyed through the conveyor, for example, an adjustment between the typical 28 mm thread diameter bottle neck and the 38 mm thread diameter bottle neck. The flanges are secured in the grooves in their relative adjusted positions by a series of set screws that are spacially arranged along the length of the conveyor channel side walls and are tightened down to secure the flanges in their adjusted positions in the opposed grooves of the side walls.
Although the ability to adjust the lateral spacing between the opposed flanges of an air conveyor is a very desirable feature in order to be able to use the same air conveyor in conveying plastic bottles of different neck diameters, the desirable flange lateral adjustment feature of this type of air conveyor has the disadvantage of the time required to adjust or change the lateral spacing between the flanges of each conveyor section. For each conveyor section the series of set screws along the lower sections of the conveyor channel side walls must first be loosened. Then, the opposed pairs of flanges are moved to their new adjusted positions and then each of the plurality of set screws in the opposed lower sections of the channel side walls along the longitudinal length of the conveyor section must be tightened down while the pair of opposed flanges are held in their new adjusted positions. This adjustment procedure is very time consuming for a single length of an air conveyor. The time involved in the adjustments can be multiplied several times for an air conveying system that is comprised of several sections of air conveyors. In addition, the adjustment procedures present an opportunity for human error where, for example, if the lateral spacing adjustment between a pair of flanges of a downstream section of the air conveyor system is incorrectly made smaller than the adjustment of the lateral spacing between the opposed flanges of an upstream section of the air conveyor system, the reduced spacing between the downstream section flanges can result in bottles becoming jammed at the transition between the upstream section and the downstream section resulting in more down time of the air conveyor system to correct the error.
What would overcome this disadvantage of the air conveyor having adjustable slot widths is a method of automatically and simultaneously changing over the lateral slot spacing between adjacent pairs of conveyor flanges between two previously determined and previously adjusted lateral slot spacings thereby eliminating the substantial amount of conveyor down time presently needed for such an adjustment. In addition, by enabling the change over of the lateral slot spacing between two previously adjusted spacing distances, the potential for human error that is present each time the lateral slot spacing is adjusted manually is also eliminated.
The present invention overcomes the disadvantages described above by providing a mechanism for quickly changing over the lateral spacing width between pairs of opposed flanges of one or more air conveyor sections between two previously determined and previously adjusted spacing distances, for example the lateral spacing distances that accommodate both the typical 28 mm thread diameter plastic bottle and the 38 mm thread diameter plastic bottle. The flange slot lateral spacing change over mechanism can be employed in newly manufactured air conveyor sections and can also be retrofit to air conveyor sections such as that disclosed in the previously referenced U.S. Pat. No. 5,628,588 as well as other types of air conveyors.
The change over mechanism of the invention employs air channel lower side wall sections that are similar to but replace lower side wall sections of the type disclosed in the above-referenced patent. The lower side wall sections, when connected to the side walls of the air conveyor channel, define mutually opposed grooves in which the adjustable flanges are received just as in the prior art air conveyor. The mutually opposed pairs of flanges of each air conveyor section are received in the mutually opposed grooves with the grooves being dimensioned sufficiently large to enable the opposed pairs of flanges to easily slide in the grooves laterally toward and away from each other. However, the pairs of flanges differ from the prior art flanges in that a series of longitudinally spaced, internally threaded holes pass through the flanges between their top and bottom surfaces.
A plurality of L-shaped brackets are mounted in lateral notches in both lower side wall sections of the air conveyor channel for laterally reciprocating movement toward and away from each other. Each of the L-shaped brackets has a horizontally extending arm that is connected to the underside of each of the opposed flanges by a screw threaded into one of the internally threaded screw holes of the flanges. A downwardly depending leg of each of the brackets passes through the bottoms of the side wall lower sections.
A plurality of actuator mechanisms, equal in number to the brackets, are secured in longitudinally spaced positions along the undersides of each of the air channel side wall lower sections. Each of the actuators includes a piston housing and a laterally reciprocating double-acting piston contained in the housing. Each piston has an inboard rod end projecting from an inboard side of the piston housing facing the slot of the air conveyor and an outboard rod end projecting from an outboard side of the piston housing facing away from the slot of the air conveyor. The downwardly depending legs of the brackets are connected to the inboard rod ends of the pistons. The pistons are mounted in the piston housings for laterally reciprocating movement between first and second positions of the pistons relative to the housing. The reciprocating movement of pistons to their first positions of the pistons moves the brackets attached to the pistons and the opposed flanges attached to the brackets laterally inwardly toward each other, positioning the flanges in their first relative positions. In the first relative positions of the flanges the first lateral spacing or slot width between the flanges is the smaller of the two predetermined lateral spacings between the pair of flanges. On reciprocating movement of the pistons to their second positions, the brackets attached to the pistons are moved laterally away from each other causing the flanges attached to the brackets to also move laterally away from each other to their second relative positions. In the second relative positions of the flanges, the second lateral spacing between the opposed pair of flanges is the larger of the two predetermined lateral spacings between the flanges.
The opposing inboard and outboard rod ends of each piston of each actuator mechanism have an adjustment mechanism. On the inboard piston rod end, the adjustment mechanism is a set screw screw-threaded in the downwardly depending leg of the bracket attached to the inboard piston rod end. By turning the set screw into and out or the downwardly depending leg of the bracket, the relative position of the inboard piston rod end to the piston housing when the piston is moved to its second position relative to the housing can be adjusted. An arm is attached to the opposite outboard rod end of the piston and an additional set screw is screw-threaded into the arm. By turning the set screw into and out of the arm, the position of the outboard piston rod end relative to the piston housing when the piston is moved to its first position relative to the housing can be adjusted.
Each of the double-acting piston actuator mechanisms is connected with a pneumatic circuit that selectively supplies pneumatic pressure to the actuator through two separate supply lines. When pneumatic pressure is supplied through the first supply line, the piston of each actuator is moved to its first position relative to the piston housing. When the pneumatic pressure is supplied to the piston actuators through the second supply line, the piston of each actuator is moved to its second position relative to the piston housing. In this manner, the opposed flanges of the air conveyor can be selectively and simultaneously moved between their first and second lateral spacing positions by the control of pneumatic pressure supplied to the piston actuators.
Where a series of air conveyors of the type described above are connected together end-to-end, it is often desirable to position the upstream ends of each opposed pair of flanges of the air conveyor sections at a slightly greater distance therebetween than the downstream ends when the opposed flanges are moved to both their first and second lateral spacing positions. This ensures that the lateral spacing between the pair of flanges of an upstream conveyor section will be slightly smaller than the lateral spacing between the pair of flanges of a downstream air conveyor section in both adjusted positions of the pairs of flanges for the two sections of air conveyor. This xe2x80x9ctoe-in/toe-outxe2x80x9d arrangement of the adjacent pairs of flanges in the sequential conveyor sections prevents the potential for bottle necks and rings being nicked or scratched in the transition of the upstream air conveyor flanges to the downstream air conveyor flanges. However, the toe-in/toe-out arrangement of adjacent pairs of flanges is not necessary in the operation of the invention and it is preferable that the flanges are adjusted to positions where there is a smooth transition from the upstream pair of flanges to the downstream pair of flanges.
The lateral slot spacing adjustment of the air conveyor may be employed in single conveyor path air conveyors and may also be employed in multiple conveyor path air conveyors where the multiple of conveyor paths extend side-by-side with each other.